An investigation is under way into a fire that broke out on June 11 at Phillips 66's 59,000-b/d Billings, Mont., refinery, the company said.

The fire, which struck the refinery's large crude unit (LCU), was quickly extinguished by on site emergency response personnel, Dennis Nuss, spokesman for Phillips 66, told OGJ via e-mail.

Following the incident, Phillips 66 personnel were dispatched to monitor air quality in the area surrounding the refinery, and data collected indicates there have been no offsite impacts, the company reported.

No injuries resulted from the fire, and all Phillips 66 personnel are safe, Nuss added.

With the cause of the fire still under investigation, Nuss said it would be premature to speculate on what, if any, impact this incident will have on operations or production at the refinery.

The current status of LCU was not disclosed.

Earlier in the month Montana regulators issued the Billings refinery a final air-quality permit incorporating administrative amendments to the site's previous permit, according to documents dated June 5 recently posted on the Montana Department of Environmental Quality's web site.